For words that only have three letters, there isn't any 4th letter. One example is with the word “incorporate”, there aren't any a lot more letters afterwards and so need to be the word "insert". The word “addict” is while in the BIP39 wordlist however you might have utilised “addi” https://sirketlist.com/story20679169/the-5-second-trick-for-ledger-seed-phrase-bip39